Hi all, first time poster. 

My home is an apartment spanning roughly 230 square meters or 2500 sqft. 

Network is set up: 

Fiber to the home from local ISP -> Fiber Modem -> uplink to Main Deco working as Router -> Tp Link Desktop unmanaged 8-port swtich -> 5 more Decos via wired backhaul -> Devices

6 X50 Decos spread across the house. 

Many devices connected (7 LG WebOS IPTVs, multiple Macs, iphones, ipads, a few smart home devices.) anything that can be wired to a port is wired, rest wireless. 

I've been facing issues of disconnects. they are intermittent but pretty frequent. total down time adds up to maybe 40 min /day (based on Connection Monitor from SofrPerfect Networx) and I run pings to 8.8.8.8, and they just fail for like 1 or a few seconds here and there.

When there is no outage, everything works great, gigabit speed everywhere, wired or else, or very close to it!

Obviously first check the ISP - trouble is the ISP is repeatly saying their own diagnostics say all is well. 

Deco says everything looks ok in the app. I noticed that the x50 router is running at high cpu often (just checking the admin interface- often at 80 or 90 percent). 

I'm looking for ideas on how to test everything but the ISP, that stuff that's within my realm. How do I systematically find what's wrong? could it be that the Desktop switch which is unmanaged (and fully booked - all 8 ports) is dropping stuff? could it be that the X50 is having a hard time beign the router for all of these devices? 

what series of tests to find the answer.

thank you for reading

Tzvika